The results of two studies evaluating Oncotype DX were presented at the 2013 Gastrointestinal Cancers Symposium in San Francisco and the data indicated that the colon cancer test may reduce medical costs, improve patient wellbeing, and change treatment recommendations.
Gene expression profiling explores the patterns of genes that are active in tumor cells. Studies suggest that gene expression may provide important information about prognosis or likely response to treatment in several types of cancer. For example, among women with early-stage, estrogen receptor-positive breast cancer, the Oncotype DX breast cancer test has been shown to predict the likelihood of cancer recurrence and the likelihood of benefit from chemotherapy. As a result, the test has been added to medical guidelines for early-stage breast cancer.
A similar test became available for colon cancer patients in 2010. The test was originally developed for use in patients with Stage II colon cancer, but has now also been validated among patients with Stage III colon cancer. The test evaluates 12 genes in a sample of tumor tissue and generates a Recurrence Score. The Recurrence Score provides information about the likelihood of cancer recurrence.
Oncotype DX Colon Cancer Test Changes Treatment Decisions
Researchers from the Mayo Clinic Cancer Research Consortium conducted a prospective study to evaluate the impact of Recurrence Score results on treatment recommendations. The analysis included 141 patients with stage II, T3, mismatch repair-proficient (MMR-P) colon cancer.
Each patient’s tumor specimen was assessed by the Recurrence Score test (quantitative RT-PCR) and MMR (IHC). Prior to and after receiving these results, physicians completed surveys indicating their planned treatments. The results indicated that the use of the Oncotype DX Colon Cancer test changed treatment decisions 45 percent of the time and led to an overall reduction in chemotherapy use.
For patients whose treatment recommendations changed, treatment intensity decreased for more than 33 percent of patients (from chemotherapy to observation or from oxaliplatin-containing to non-oxaliplatin containing regimens) and increased for more than 11 percent of patients (from observation to any chemotherapy or from non-oxaliplatin containing to oxaliplatin-containing treatment). The researchers concluded that use of the Oncotype DX Colon Cancer test may lead to overall reductions in chemotherapy.
Oncotype DX Colon Cancer Test is Cost Effective
Researchers from the Mayo Clinic Cancer Research Consortium conducted an analysis of 141 patients at 17 sites to evaluate the economic value of using the Oncotype DX test to identify stage II colon cancer patients with low risk of recurrence. After receiving the Recurrence Score results, physician recommendations for adjuvant chemotherapy in patients with low risk of recurrence decreased by 22 percent, which resulted in direct medical care costs savings of $4,200 per patient.
 Srivastava G, Renfro LA, Behrens RJ, et al. Prospective evaluation of a 12-gene assay on treatment recommendations in patients with stage II colon cancer. Journal of Clinical Oncology. 2012; 30(suppl 34): Abstract 453.
 Alberts SR, Yu T, Behrens RJ, et al. Real-world comparative economics of a 12-gene assay for prognosis in stage II colon cancer. Journal of Clinical Oncology. 2012; 30(suppl 34): Abstract 391.